The United States should stop going out of its way to avoid calling the military initiative against the Islamic State (ISIS) a war, former U.S. ambassador to the United Nations Mark Wallace says.

"We're clearly at war. This is absolutely a war, but we're too defensive on that. Why should we shy away?" Wallace said Monday on "The Steve Malzberg Show" on Newsmax TV.

"It's a threat to the United States national security, global peace and security, and I don't think we should be defensive about it."